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Abstract:

A touch sensor configuration contains an optically transparent substrate,
at least one optically transparent touch sensor element formed on the
substrate and has at least one electrically conductive, transparent
layer, and at least one contacting structure for the electrical
contacting of the electrically conductive, transparent layer. The
contacting structure has in direct contact with the electrically
conductive, transparent layer at least one layer of MoxTay with
0.02≦y≦0.15.

Claims:

1. A touch sensor configuration, comprising: an optically transparent
substrate; at least one optically transparent touch sensor element formed
on said substrate and having at least one electrically conductive,
transparent layer; and at least one contacting structure for electrical
contacting of said electrically conductive, transparent layer, said
contacting structure having in direct contact with said electrically
conductive, transparent layer at least one layer of MoxTay with
0.02.ltoreq.y≦0.15.

3. The touch sensor configuration according to claim 1, wherein said
contacting structure is of a multilayer structure and has at least one
layer of Al, Cu, Ag, Au, an Al alloy with an Al content ≧90 atomic
percent, a Cu alloy with a Cu content ≧90 atomic percent, an Ag
alloy with an Ag content ≧90 atomic percent or an Au alloy with an
Au content ≧90 atomic percent.

4. The touch sensor configuration according to claim 1, wherein said
contacting structure has at least one contact terminal for connection to
an electronic activation and evaluation unit and an exposed surface of
said contact terminal is formed by said at least one layer of
MoxTay with 0.02.ltoreq.y≦0.15.

5. The touch sensor configuration according to claim 1, wherein the touch
sensor configuration forms part of a touch sensor screen.

6. The touch sensor configuration according to claim 1, wherein said
optically transparent touch sensor element is one of a plurality of touch
sensor elements disposed in a grid.

7. The touch sensor configuration according to claim 1, wherein said at
least one electrically conductive, transparent layer has one of a
transparent conductive oxide, a transparent, conductive polymer or a
coating of carbon nano-tubes.

8. The touch sensor configuration according to claim 1, wherein said
optically transparent substrate has a rear side facing away from the
touch sensor configuration, and forms a substrate for at least one
component of a liquid crystal display.

9. A method, which comprises the step of: forming, via a sputtering
target, a contacting structure in direct contact with an electrically
conductive, transparent layer of an optically transparent touch sensor
element of a touch sensor configuration that is formed on an optically
transparent substrate, the sputtering target containing MoxTay
with 0.02.ltoreq.y≦0.15.

10. The method according to claim 9, which further comprises setting y in
the range of 0.03.ltoreq.y≦0.09.

11. A method, which comprises the step of: providing and using an etching
solution for structuring a contacting structure for contacting an
electrically conductive, transparent layer, the contacting structure
having at least one layer of MoxTay with
0.02.ltoreq.y≦0.15 and the etching solution having at least one of
phosphoric acid, acetic acid or nitric acid as solution constituents.

12. The method according to claim 11, which further comprises setting a
proportion of phosphoric acid to be 60-90 percent by weight, a proportion
of acetic acid to be 0-20 percent by weight and a proportion of nitric
acid to be 1-12 percent by weight.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the priority, under 35 U.S.C. §119, of
Austrian application GM 77/2010, filed Feb. 12, 2010; the prior
application is herewith incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The present invention relates to a touch sensor configuration.

[0003] Touch sensors are being used increasingly frequently in electronic
devices. In particular, in recent years touch sensors have often been
used as an intuitive-to-operate, user-friendly interface for entering
information into navigation systems, personal digital assistants (PDA),
portable minicomputers, cell phones, PC systems, copiers, etc. In many
cases, the touch sensor or a configuration of a plurality of touch
sensors is arranged over a display unit, which may be formed for example
by a screen, such as for example an active-matrix liquid-crystal screen
(TFT-LCD, thin film transistor liquid crystal display). The touch sensor
or the touch sensor configuration is in this case often formed in such a
way that a user can communicate with the electronic device by touching it
with a finger, a tracer or some other object.

[0004] In this respect, various measuring principles are known for
determining the touching point on a surface of the touch sensor or the
touch sensor configuration. The various measuring principles are also
used for classifying the various types of touch sensors or touch sensor
configurations. For example, a distinction is made between resistance
sensing (resistive sensing), capacitive sensing, acoustic sensing,
optical sensing (for example in the visible range or in the infrared
range) and sensing by electromagnetic induction (inductive sensing). Most
of the touch sensors or touch sensor configurations that are on the
market use resistive or capacitive sensing for determining the position
of the touching point. A capacitive touch sensor configuration has two
electrically conductive layers, applied to an electrically insulating
substrate. The two electrically conductive layers may, for example, be
applied to the opposite surfaces of the substrate, at least substantially
over their full area, or just to one side of the substrate. If applied to
only one side of the substrate, the layers may, for example, be arranged
next to one another in a grid configuration or one above the other,
separated by an electrically insulating layer.

[0005] In the case of a configuration over a display unit, the touch
sensor or the touch sensor configuration must be of an optically
transparent form (at least to the greatest extent), in order that the
user can see the display unit.

[0006] It is known in the case of such touch sensors to provide
electrically conductive, transparent layers as electrodes of touch sensor
elements. The electrically conductive and optically transparent layers
concerned are, for example, in many cases produced from a transparent
conductive oxide (TCO, transparent conducting oxide), such as for example
indium tin oxide (ITO), indium zinc oxide (IZO), aluminum zinc oxide
(AZO) or antimony tin oxide, an electrically conductive polymer film or a
similar material.

[0007] U.S. patent publication No. 2009/0096759 A1 describes a touch
sensor configuration on a screen. It describes touch-sensitive screens in
which an optically transparent touch electrode is arranged on an
insulating substrate and a touching position on the touch electrode is
determined by electrical signals. In the first to third embodiments, a
touch sensor configuration of the capacitive type (capacitance sensing)
is described, and in further embodiments a touch sensor configuration of
the resistive type (resistance sensing) is described.

[0008] U.S. patent publication No. 2009/0160824 A1 describes a
two-dimensional sensor structure for a touch-sensitive screen of the
capacitive type. A plurality of optically transparent touch sensor
elements are provided, arranged in a grid on a screen (with different
positions in a first direction and a second direction perpendicular
thereto). The optically transparent touch sensor elements are
electrically contacted by a metallic contacting structure. The metallic
contacting structure is in this case applied as a layer to an insulating
glass substrate.

[0009] To make it possible to sense touch signals or position signals, in
the various touch sensor configurations described above the electrically
conductive, transparent layers must be electrically connected to an
evaluation unit. To obtain a touch sensor configuration provided with the
desired properties with respect to measuring accuracy and measuring
speed, the electrical connection to the evaluation unit usually takes
place by way of a metallic contacting structure, which has a higher
conductivity (usually by 2 to 3 orders of magnitude) than the
electrically conductive, transparent layers of the electrodes of the
touch sensor. Metallic conductor tracks are usually used in this respect.
The electrically conductive, transparent layers and the contacting
structure are usually coated with a transparent, non-conducting
protective layer, which is intended to protect the sensor layers lying
thereunder from corrosion, moisture, perspiration, contaminants and
damage, for example caused by scratches. Both the application of the thin
electrically conductive, transparent layers and the application of the
contacting structure usually take place by way of cathode sputtering and
deposition on the substrate. The creation of the touch sensor
configuration usually involves a structuring of the individual layers by
way of photolithography in combination with a wet-chemical etching
process. The passivation layer (protective layer) is usually deposited by
chemical vapor deposition (CVD) and structured by wet or plasma etching.

[0010] In the production of such touch-sensitive configurations by way of
layer depositing processes, a further problem occurs in particular in the
case of substrates with a large area, such as for example in the
production of large-area touch-sensitive screens. When depositing the
contacting structures and the electrically conductive, transparent
layers, different tensile stresses or compressive stresses occur in a
plane parallel to the substrate surface on account of different
coefficients of thermal expansion and on account of further parameters of
the depositing process (in particular the pressure of the working gas and
the substrate temperature in the case of cathode sputtering) in the
region of the substrate and the layers applied thereto. These differences
in stress may, for example, thereby cause an upward distortion of the
substrate, which leads to undesired effects, particularly in the case of
large-area touch-sensitive screens. In extreme cases, this may even lead
to destruction of the substrate. Furthermore, these effects may cause the
contacting structures to undergo undesired deformation. With excessive
tensile stresses, cracks may occur in the layer, with excessive
compressive stresses upward distortions or folding may occur. For
example, when aluminum or aluminum alloys are used as the material for
the contacting structures, so-called hillocks form, i.e. undesired
deformations of the surface of the contacting structure. In a subsequent
step of the production process, these may cause poorer layer formation or
layer coverage and further problems, such as for example a short circuit
of the touch sensor. When aluminum or aluminum alloys are used for the
contacting structure, furthermore, special measures have to be taken to
provide electrical contacting with a low transfer resistance in relation
to the electrically conductive, transparent layers.

[0011] Particularly in the case of portable devices, such as for example
cell phones, PDAs, navigation devices and the like, during operation the
touch sensor or the touch sensor configuration is exposed to high stress
due to environmental influences (corrosion, moisture, perspiration,
etc.). Furthermore, due to the often very thin protective layer, which is
usually only a few micrometers thick, sometimes oxidizing substances (for
example oxygen, etc.) can diffuse through and react with the layers
located thereunder. This can cause damage to the metallic contacting
structure by corrosion or oxidation. This damage may lead to changing of
the electrical conductivity (usually a deterioration) of the contacting
structure, which in turn may result in errors in the determination of the
touching position. In extreme cases, it may cause a complete electrical
interruption of the contacting structure.

[0012] The contacting structure in the case of such touch sensor
configurations must therefore meet many different requirements. The
material of the contacting structure must on the one hand be good in
terms of being worked in an etching process during production, i.e. be
good in terms of being etched, or have a good etching behavior, and on
the other hand have a high corrosion resistance and resistance to
external influences in the application of the touch sensor configuration.
Furthermore, the contacting structure must have a relatively high
electrical conductivity and a low transfer resistance in relation to the
respective electrically conductive, transparent structure. In addition,
undesired effects caused by different tensile stresses and compressive
stresses in the individual layers must be kept as small as possible or be
compensated.

SUMMARY OF THE INVENTION

[0013] It is accordingly an object of the invention to provide a touch
sensor configuration which overcomes the above-mentioned disadvantages of
the prior art devices of this general type.

[0014] With the foregoing and other objects in view there is provided, in
accordance with the invention a touch sensor configuration. The touch
sensor configuration contains a contacting structure for an electrical
contacting of an electrically conductive, a transparent layer that
achieves a most advantageous possible etching behavior with at the same
time good corrosion resistance and other resistance, highest possible
electrical conductivity with lowest possible transfer resistance as well
as avoidance as completely as possible of disadvantageous influences
caused by mechanical stress gradients in the individual layers.

[0015] The touch sensor configuration has an optically transparent
substrate, at least one optically transparent touch sensor element, which
is formed on the substrate and has at least one electrically conductive,
transparent layer, and at least one contacting structure for the
electrical contacting of the electrically conductive, transparent layer.
The contacting structure has in direct contact with the electrically
conductive, transparent layer at least one layer of MoxTay with
0.02≦y≦0.15.

[0016] "Touch" or "touching" is understood here as meaning not only direct
touching, with direct physical contact, but also when an object is
brought into the direct vicinity of a sensor element in such a way that
the latter can sense it approaching. A touch sensor configuration is
understood here as meaning a configuration which makes it possible to
sense when a touch sensor element is touched with a finger, a tracer or
some other object or the latter is at least brought into the direct
vicinity of the touch sensor element. In particular, the touch sensor
element may be configured, for example, for resistive or capacitive
sensing, as described at the beginning. The touch sensor configuration
may, in particular, be formed as an interface for entering information
into an electronic device, in particular in such a way that a user can
communicate with the electronic device by touching it with a finger, a
tracer or some other object.

[0017] Optically transparent or transparent is understood here as meaning
that the respective layers or structures are transparent, at least to the
greatest extent, to light in the visible range, so that the light in the
visible range can pass through unhindered, at least to the greatest
extent.

[0018] The designation MoxTay with 0.02≦y≦0.15
generally means an alloy where: x+y=1. The figures given for x and y in
the present description always refer to atomic percent. However, it
should be noted that this does not have to be MoxTay of the
highest purity, but that impurities with other elements may be present.
At least one layer of MoxTay is understood here as meaning that
the contacting structure may also have in addition to the layer of
MoxTay one or more further layers of one or more other
materials, or else a number of layers of MoxTay may be
provided, possibly in combination with one or more other layers. However,
it is also possible to produce the contacting structure exclusively from
MoxTay, since this has a high electrical conductivity. In this
case, a simplified layer structure is provided--in comparison with known
touch sensor configurations, in which the contacting structure is formed
from a number of layers of different materials.

[0019] Since the contacting structure in direct contact with the
electrically conductive, transparent layer has at least one layer of
MoxTay with 0.02≦y≦0.15, the contacting structure
has a low electrical resistance and, in particular, a low transfer
resistance is provided in relation to the electrically conductive,
transparent layer. It has also been found that the layer of
MoxTay with 0.02≦y≦0.15 exhibits a particularly
advantageous etching behavior during production, i.e. is good in terms of
being etched in a wet-chemical etching process, but on the other hand
also has a high corrosion resistance and other resistance in the finished
touch sensor configuration. This property is brought about by the
MoxTay with 0.02≦y≦0.15 being good in terms of
being worked in the usual chemical processes that are used in
wet-chemical etching, but on the other hand having a high resistance in
respect of the corrosion processes and atmospheric oxidation processes
that usually occur undesirably and take place under other ambient
conditions and with other pH values. With the layer of MoxTay
with 0.02≦y≦0.15, the stress conditions on the substrate
can also be controlled very well during the production of the touch
sensor configuration, so that distortion of the substrate can be avoided
and good layer adherence can be achieved. In particular in the case of a
multilayer structure of the contacting structure with at least one
further layer of Al or an Al alloy in a proportion of Al≧90 atomic
percent (in particular for example AlNd alloy), which causes a tensile
stress in a plane parallel to the substrate surface, the layer of
MoxTay with 0.02≦y≦0.15 brings about good stress
compensation in the layer structure as a whole. In comparison with a
layer of MoaNbb, for example, a lower resistance of the
contacting structure is provided by the layer of MoxTay, the
etching behavior and the corrosion resistance are significantly improved
and improved stress compensation is achieved in the layer structure as a
whole.

[0020] It is preferred for the layer of MoxTay that:
0.03≦y≦0.09. It has been found that, with this relationship
in particular, the advantages described above are achieved to a
particularly high degree.

[0021] According to one configuration, the contacting structure is of a
multilayer structure and has at least one layer of Al or Cu or Ag or Au
or Al alloy (with an Al content ≧90 atomic percent) or Cu alloy
(with a Cu content ≧90 atomic percent) or Ag alloy (with an Ag
content ≧90 atomic percent) or Au alloy (with an Au content
≧90 atomic percent). In this case, a particularly high electrical
conductivity of the contacting structure is achieved by the at least one
layer of Al, Cu, Ag or Au or the alloys thereof and the electrical
connection to the electrically conductive, transparent layer is produced
by the layer of MoxTay. With the MoxTay layer formed
between the substrate and the layer of Al, Cu, Ag, Au or the alloys
thereof, improved adherence on the substrate is also achieved in
particular. The contacting structure may in this case preferably have a
two-layer or three-layer structure. In the case of Cu alloys, alloys with
Mg, Ca and/or Mn may be used in particular. The layer of MoxTay
provides the described advantageous etching behavior and the high
corrosion resistance and other resistance of the contacting structure.
Particularly preferred is a layer structure of the contacting structure
with at least one layer of Al or an Al alloy with an Al content
≧90 atomic percent, in particular AlNd alloy, and the at least one
layer of MoxTay. In this case, the at least one layer of
MoxTay protects the layer of Al or Al alloy reliably from the
formation of an insulating surface layer of aluminum oxide and ensures
reliable electrical contacting of the electrically conductive,
transparent layer. Particularly in the case of this combination, the
layer of MoxTay achieves particularly advantageous compensation
for the stresses introduced by the layer of Al or Al alloy and suppresses
the formation of undesired deformations of the surface, such as for
example so-called hillocks. In a particularly preferred configuration,
the contacting structure has a two-layer structure with a layer of Al or
Al alloy and the layer of MoxTay or a three-layer structure
with a layer of MoxTay, a layer of Al or Al alloy and a further
layer of MoxTay.

[0022] According to one configuration, the contacting structure of the
touch sensor configuration has at least one contact terminal for the
connection to an electronic activation and evaluation unit and an exposed
surface of the contact terminal is formed by the at least one layer of
MoxTay with 0.02≦y≦0.15. Since electrical
connection to an electronic evaluation unit is required for the touch
sensor configurations and this electrical connection is generally only
formed completely in a working step that takes place at a time well after
the touch sensor configuration is formed, in these cases a number of
contact terminals are generally required. Since the contact terminals are
exposed to very different ambient conditions (often also over relatively
long periods of time, for example during storage and/or transport), they
must have not only high electrical conductivity but also high corrosion
resistance and other resistance, which is achieved by the at least one
layer of MoxTay. The at least one layer of MoxTay on
the exposed surface of the at least one contact terminal allows undesired
corrosion to be prevented at this location. Furthermore, the desired
configuration of contact terminals can in this case be performed in the
same process step as the formation of the contacting structure, so that
an efficient production process with few steps is made possible.

[0023] According to one configuration, the touch sensor configuration
forms part of a touch sensor screen (touchscreen). Particularly in this
case, the touch sensor configuration is exposed to loads due to
environmental influences, such as for example corrosion, moisture,
perspiration or mechanical effects, to a great extent during operation. A
high corrosion resistance and other resistance is achieved for this
application in particular by the claimed configuration of the touch
sensor configuration.

[0024] According to one configuration, the touch sensor configuration has
a plurality of touch sensor elements arranged in a grid. Particularly in
the case of such a configuration, the contacting structure must provide
contacting of the number of touch sensor elements that is resistant and
has good electrical conductivity, which is achieved by the claimed
combination of features. "Arranged in a grid" is understood here as
meaning that the touch sensor elements are arranged in a predetermined
pattern at various locations on the surface of the substrate. However,
the pattern is not restricted here to an orthogonal configuration (for
example in the manner of a checkerboard).

[0025] According to one configuration, the at least one electrically
conductive, transparent layer has a transparent conductive oxide (TCO,
transparent conducting oxide), a transparent, conductive polymer or a
coating of carbon nano-tubes. On account of their optical transparency
and electrical conductivity, these materials are particularly suitable
for the configuration of touch sensor configurations that are used in
touch-sensitive screens. Indium tin oxide (ITO), indium zinc oxide (IZO),
aluminum zinc oxide (AZO) or antimony tin oxide may be used here in
particular as transparent conductive oxides. It has been found that the
at least one layer of MoxTay shows the described advantageous
properties in particular when contacting with these materials.

[0026] According to one configuration, the rear side of the optically
transparent substrate, facing away from the touch sensor configuration,
forms a substrate for at least one component of a liquid crystal display.
In this case, a so-called "in-cell" touch sensor configuration is
provided, in the case of which the touch sensor configuration does not
have a separate substrate with respect to a screen located thereunder.
Particularly in the case of such a configuration, the avoidance of
undesired stresses in the substrate is important, and is achieved by the
specified touch sensor configuration, as described above. However, it is
also possible, for example, to form the touch sensor configuration and
the at least one component of the liquid crystal display on the same side
of the substrate, preferably on the side that does not form the outer
side during operation.

[0027] The sputtering target is used for forming a contacting structure in
direct contact with an electrically conductive, transparent layer of an
optically transparent touch sensor element of a touch sensor
configuration that is formed on an optically transparent substrate. The
sputtering target contains MoxTay with
0.02≦y≦0.15. Use of this sputtering target for forming the
contacting layer allows the contacting layer to be created by deposition
on the substrate by cathode sputtering. In this case, a high electrical
conductivity of the contacting structure is achieved with low electrical
transfer resistance in relation to the electrically conductive,
transparent layer, good corrosion resistance and other resistance of the
contacting structure as well as excellent compensation for stresses in a
plane parallel to the surface of the substrate. This is achieved to a
particularly great extent if: 0.03≦y≦0.09. The object is
also achieved by the use of an etching solution for structuring a
contacting structure for contacting an electrically conductive,
transparent layer. The contacting structure has at least one layer of
MoxTay with 0.02≦y≦0.15. The etching solution has
phosphoric acid and/or acetic acid and/or nitric acid as solution
constituents. The proportion of phosphoric acid is preferably 60-90
percent by weight, the proportion of acetic acid is preferably 0-20
percent by weight and the proportion of nitric acid is preferably 1-12
percent by weight. The possibly remaining proportion may be formed by
water and possibly wetting agent (for example a fluoride-containing
compound or an anionic additive).

[0028] Other features which are considered as characteristic for the
invention are set forth in the appended claims.

[0029] Although the invention is illustrated and described herein as
embodied in a touch sensor configuration, it is nevertheless not intended
to be limited to the details shown, since various modifications and
structural changes may be made therein without departing from the spirit
of the invention and within the scope and range of equivalents of the
claims.

[0030] The construction and method of operation of the invention, however,
together with additional objects and advantages thereof will be best
understood from the following description of specific embodiments when
read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0031]FIG. 1 is a diagrammatic, plan view of a structure of a touch
sensor configuration according to a first embodiment of the invention;

[0032]FIG. 2 is a diagrammatic, illustration showing various regions of
the touch sensor configuration in a view perpendicular to a surface of a
substrate; and

[0033]FIG. 3 is a diagrammatic, illustration showing the various regions
of the touch sensor configuration in a case of a second embodiment
according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0034] Referring now to the figures of the drawing in detail and first,
particularly, to FIGS. 1 and 2 thereof, there is shown a first embodiment
of the present invention. In the case of the first embodiment, a touch
sensor configuration 10 forms part of a touch sensor screen
(touchscreen). In the case of the embodiment represented, the touch
sensor configuration is configured as a so-called "in-cell" touch sensor
configuration, in which an optically transparent substrate 1 of the touch
sensor configuration 10 at the same time forms the color filter substrate
of an LCD screen. A rear side of the optically transparent substrate 1,
facing away from the touch sensor configuration, consequently forms a
substrate for at least one component of a liquid crystal display.
However, the way in which the touch sensor configuration is implemented
is not restricted to such a configuration. The substrate 1 may, for
example, also be formed as a separate substrate, for example of glass or
transparent plastic, and may be formed, for example, as a rigid plate or
a flexible sheet. However, in all these cases the optically transparent
substrate 1 consists of an electrically insulating material.

[0035] In the case of the embodiment represented, the touch sensor
configuration 10 is formed in such a way that a plurality of touch sensor
elements, which in FIG. 1 are shown as square for example, are arranged
in the form of a measuring area on the surface of the substrate 1.
However, the touch sensor configuration is not restricted to such a
configuration. In the case of the example, the touch sensor configuration
is a configuration for capacitive sensing. In the case of the exemplary
embodiment represented, the function and structure of the touch sensor
configuration correspond substantially to that described in U.S. patent
publication 2009/0160824 A1, but the configuration is not restricted to
this structure. For example, it is also possible to configure the touch
sensor configuration for resistive sensing.

[0036] In the case of the embodiment represented, the two conductive
layers (electrodes) required for the capacitive sensing on the same side
of the substrate are structured in a checkerboard-like pattern in a grid
of rows and columns. On account of the structuring, a plurality of touch
sensor elements are consequently formed, forming the two electrodes for
capacitive sensing. The two electrodes of the capacitive touch sensor
configuration 10 are produced from the same material, that is to say from
an electrically conductive, optically transparent layer 4. To illustrate
this clearly, the two electrodes are shown in FIG. 1 as shaded
differently. The touch sensor elements 4x of one electrode side are shown
as shaded horizontally and the touch sensor elements 4y of the other
electrode side are shown as shaded vertically. The touch sensor elements
4x are connected to one another in an electrically conducting manner in
the (horizontal) rows by way of their respective corners (as
schematically represented in FIG. 1 by solid lines). The touch sensor
elements 4y are likewise connected to one another in an electrically
conducting manner in the vertical columns by way of their respective
corners (as schematically represented in FIG. 1 by dashed lines). The
connection of the individual touch sensor elements may in this case be
formed, for example, from the material of the touch sensor elements 4x,
4y, that is to say from the electrically conductive, transparent layer 4,
or for example from the material of the contacting structure, which is
described below. In the case of the exemplary embodiment, the
electrically conductive, transparent layer 4 is produced from a
transparent conductive oxide (TCO, transparent conducting oxide), which
is applied to the substrate by way of cathode sputtering (sputter
deposition). The conductive, transparent layer 4 may be formed in
particular from indium tin oxide (ITO), indium zinc oxide (IZO), aluminum
zinc oxide (AZO) or antimony tin oxide. However, it is also possible for
example to form the conductive, transparent layer 4 from an electrically
conductive polymer film. In regions 7, in which the connections of the
columns and the connections of the rows cross, they are formed in each
case as electrically insulated with respect to one another, which may be
implemented, for example, by an electrically insulating layer arranged in
between.

[0037] The respective rows of the touch sensor elements 4x are connected
by way of an electrically conducting contacting structure 2 to contact
terminals 6, which are respectively formed by a region of the contacting
structure 2. Similarly, the respective columns of the touch sensor
elements 4y are connected by way of the contacting structure 2 to further
contact terminals 6, which are likewise respectively connected by a
region of the contacting structure. The contact terminals 6 are formed
for the purpose of providing an electrical connection to an electronic
activation and evaluation unit, by way of which respective voltages can
be applied to the electrodes of the touch sensor elements 4x, 4y, in
order to detect touching of the touch sensor configuration 10 and
evaluate it with respect to its position. The contact terminals 6 are,
for example, formed as regions to which connecting cables on the touch
sensor configuration 10 can be attached, for example by soldering or
brazing, adhesive attachment with an electrically conductive adhesive,
bonding, etc.

[0038] The structure of the individual components of the touch sensor
configuration 10 is described in more detail below with reference to FIG.
2. In FIG. 2, various regions B1, B2, B3 and B4 of the touch sensor
configuration 10 are represented. The region B1 is located in the region
of the contact terminals 6. The region B2 is a region in which the
contacting structure 2 is formed, but not the electrically conductive,
transparent layer 4. The region B3 is located where the contacting
structure 2 is made to contact the electrically conductive, transparent
layer 4. The region B4 is located where no contacting structure is
formed, but only the electrically conductive, transparent layer 4.

[0039] In the region B1, the contact terminals 6 are formed on the
substrate 1 from the material of the contacting structure 2. The contact
terminals 6 are produced from a layer of MoxTay with
0.02≦y≦0.15, which is applied to the substrate by cathode
sputtering. In this region B1, the surface of the contact terminals 6 is
exposed for later electrical contacting.

[0040] In the region B2, the layer of MoxTay with
0.02≦y≦0.15 is deposited on the substrate 1, in order to
form the contacting structure 2 for the contacting of the touch sensor
elements 4x, 4y. Deposited on this layer is an optically transparent
protective layer 5, which may, for example, consist of silicon nitride.
The protective layer 5 may, for example, be deposited by chemical vapor
deposition (CVD) after the formation of the contacting structure 2 with
the contact terminals 6 and the electrically conductive, transparent
layer 4.

[0041] In the region B3, the contacting structure 2 contains the layer of
MoxTay with 0.02≦y≦0.15 is deposited on the
substrate 1 and, in direct contact with it, the electrically conductive,
transparent layer 4. The electrically conductive, transparent layer 4 is
applied, for example, by cathode sputtering. In this region B3, the
contacting structure 2 and the electrically conductive, transparent layer
4 are covered on the side facing away from the substrate 1 by the
protective layer 5.

[0042] In the region B4 there is the at least one touch sensor element. In
this region B4, the electrically conductive, transparent layer 4 is
deposited on the substrate 1 and this layer is covered on the side facing
away from the substrate 1 by the protective layer 5.

[0043] In a production process for creating the described touch sensor
configuration, the contacting structure 2 and the contact terminals 6 are
deposited on the substrate 1 by cathode sputtering (sputter deposition).
In the deposition, a sputtering target with a target area consisting of
MoxTay with 0.02≦y≦0.15 is used. By providing the
MoxTay in the form of a sputtering target, low-cost cathode
sputtering can be used as a coating method for creating the structures.
By appropriate selection of the depositing conditions, excellent
adherence of the contacting structure 2 and the contact terminals 6 on
the substrate 1 can be achieved, in particular when it is a glass
substrate. An example of suitable depositing conditions is, for example,
direct-current cathode sputtering (DC sputtering) with a DC voltage power
density of 5-10 W/cm2, argon working gas with a pressure of
2.5×10-3 to 7.5×10-3 mbar and a substrate
temperature between room temperature and 150° C.

[0044] In the production process, the electrically conductive, transparent
layer 4 and the layer of MoxTay are structured by
photolithography in combination with a wet-chemical etching process. The
etching preferably takes place in this case with an etching solution of
phosphoric acid and nitric acid and possibly acetic acid (PAN etching
solution). The proportion of phosphoric acid is in this case preferably
60-90 percent by weight, the proportion of nitric acid is preferably 1-12
percent by weight, the proportion of acetic acid is preferably 0-20
percent by weight, and the remaining proportion is formed by water, it
also being possible for a wetting agent (for example a
fluoride-containing compound or an anionic additive) to be contained. The
protective layer 5 is structured by wet or plasma etching.

[0045] In a use of the touch sensor configuration 10, voltages are applied
in a known way to the touch sensor elements 4x, 4y by an electronic
evaluation and control unit. The electronic evaluation and control unit
senses changes in capacitance that are caused by the touch sensor
elements 4x, 4y being touched or approached by a finger, a tracer or some
other object, and the x/y coordinates of the user input on the touch
sensor configuration are calculated from this in a likewise known way.

[0046] In the case of the first embodiment, the structure of the touch
sensor configuration is simplified in comparison with known touch sensor
configurations in which the contacting structure has a multilayer
structure.

[0047] A second embodiment is described below with reference to FIG. 1 and
FIG. 3. The second embodiment differs from the first embodiment only in
the structure of the contacting structure. To avoid repetition, only the
differences from the first embodiment are described below. The same
designations are retained for the same components.

[0048] As a difference from the first embodiment, in which the contacting
structure 2 is formed only by a layer of MoxTay with
0.02≦y≦0.15, the contacting structure 2', 3 in the case of
the second embodiment has a multilayer structure. In the case of the
example represented in FIG. 3, the contacting structure has a layer 3
and, formed thereupon, a layer 2' of MoxTay with
0.02≦y≦0.15. The layer 3 is formed from Al, Cu, Au, Ag, an
Al alloy with a proportion of Al≧90 atomic percent, a Cu alloy
with a proportion of Cu 90 atomic percent, an Au alloy with a proportion
of Au≧90 atomic percent or an Ag alloy with a proportion of
Ag≧90 atomic percent. The layer 3 is preferably formed from Al or
an Al alloy. The layer 3 is deposited on the substrate by cathode
sputtering. The layer 2' of MoxTay with
0.02≦y≦0.15 is deposited on the metallic layer 3 by cathode
sputtering.

[0049] With the touch sensor configuration according to the second
embodiment, substantially the same advantages as with the first
embodiment are achieved and are described in still more detail below. In
the case of the solution according to the second embodiment, however, it
is possible to provide the contacting structure with an increased
conductivity in comparison with the first embodiment, since the layer 3
provides a higher conductivity than the layer of MoxTay with
0.02≦y≦0.15. For example, a 300 nm thick MoxTay
layer has a resistivity of about 11 μohmcm and a layer containing two
layers, a 250 nm thick Al layer and a 50 nm thick MoxTay layer,
has a resistivity of about 3.5 μohmcm.

[0050] According to a modification of the second embodiment, the
contacting structure has a three-layer structure, in which a layer of
MoxTay with 0.02≦y≦0.15 is deposited on the
substrate, and the layer 3 (as described in the case of the second
embodiment) is deposited on this layer and the further layer 2' of
MoxTay with 0.02≦y≦0.15 is deposited on the
metallic layer 3. With a multilayer structure, the layer structure
according to the modification achieves particularly good adherence on the
substrate 1, in particular if the substrate 1 consists of glass.

[0051] The advantages achieved with the solution according to the
invention are explained in still more detail below. A high corrosion
resistance to atmospheric moisture, water, perspiration, etc. is achieved
by the provided touch sensor configuration with the contacting structure
2, which has at least one layer of MoxTay with
0.02≦y≦0.15. Furthermore, a high oxidation resistance to
atmospheric oxygen and other oxidizing substances in the ambient air is
achieved. At the same time, good structurability by conventional
wet-chemical etching processes in combination with photolithography
techniques is provided. The contacting structure provides a high
electrical conductivity and good adherence on the material of the
substrate 1. Good electrical contacting with a low transfer resistance in
relation to the electrically conductive, transparent layer 4 is achieved
by the layer of MoxTay with 0.02≦y≦0.15. On
account of the deposition of the layer of MoxTay with
0.02≦y≦0.15 by cathode sputtering (sputter deposition), the
deposition is performed in a stable, easy-to-control and low-cost coating
process that is available even for large-area substrates.

[0052] The production process for the overall touch sensor configuration
takes place using customary thin-film technology. The layers are first
coated over a large area onto the substrate by PVD (physical vapor
deposition) or CVD (chemical vapor deposition) processes and subsequently
structured (in each case) by photolithography processes. The required
etching step may in this case take place, for example, wet-chemically or
by a dry-etching process, a wet-chemical etching process mainly coming
into consideration for the metallic layers. The wet-chemical etching may
in this case be performed, for example, by mixtures of phosphoric acid
and nitric acid or mixtures of phosphoric acid, nitric acid and acetic
acid. For the case where there is at least one layer of Al or an Al
alloy, this involves the following processes in particular:

6HNO3→6H++6NO3- (R1)

2Al+6H+→2Al3++3H2( ) (R2)

Al+NO3-+4H+→Al3++NO( )+2H2O (R3)

H3PO4+2H2O→2H3O++HPO42- (R4)

2Al3++3HPO42-→Al2(HPO4)3→2Al-
PO4+H3PO4 (R5)

[0053] During the wet-chemical etching process, the metallic layer is
oxidized, either by protons (H+ ions) of the acid, as specified in
equation R2, or by nitrate ions, as specified in equation R3. The
oxidized, dissolved metal species is stabilized in the solution by
phosphate ions, as specified in equation R5.

[0054] From a chemical viewpoint, the undesired corrosion or atmospheric
oxidation that is intended to be avoided and the wet etching that is
required for the production process are the same processes, which however
take place under different ambient and pH conditions. While corrosion and
atmospheric oxidation are intended to take place at a reaction rate that
is as slow as possible, or not to take place at all, the oxidation
process during the wet-etching and structuring process is desired and the
reaction should take place at a sufficiently high rate. The
MoxTay with 0.02≦y≦0.15 that is used for the
formation of the contacting structure meets these conflicting
requirements.

[0055] The layer of MoxTay with 0.02≦y≦0.15 in
this case also provides high electrical conductivity. When the contacting
structure is formed with a multilayer structure and, in particular, with
a layer of Al or Al alloy, the layer of MoxTay with
0.02≦y≦0.15 also prevents the formation of an insulating
aluminum oxide layer on the surface thereof. In particular in the case of
such a multilayer structure, the layer of MoxTay with
0.02≦y≦0.15 also brings about excellent stress compensation
in the layer structure. A tensile stress introduced into the substrate
and into the layer structure through the layer of Al or Al alloy and
acting in a plane parallel to the substrate surface is compensated
particularly advantageously by a compressive stress introduced by way of
the layer of MoxTay with 0.02≦y≦0.15 and likewise
acting in the plane parallel to the substrate surface. Consequently,
resultant strains and/or deformations of the substrate are efficiently
avoided.

[0056] Although an implementation of the touch sensor configuration in
which the touch sensor configuration is arranged on the surface that is
lying on the outside during operation has been described above with
reference to the embodiments, it is also possible, for example, to
arrange the touch sensor configuration on the opposite, rear side of the
substrate. Although a so-called implementation in which both electrodes
are arranged on the same side of the substrate has been described here,
it is also possible, for example, for one electrode to be arranged on one
side of the substrate and the other to be arranged on the opposite side
of the substrate.

[0057] Although an implementation in which the electrodes of the touch
sensor configuration are arranged on the surface of the substrate in a
checkerboard pattern has been described with reference to the
embodiments, they may, for example, also be arranged in some other
pattern or grid. Furthermore, it is also possible for the electrodes not
to be arranged next to one another on the substrate surface, as in the
case of the exemplary embodiments, but one above the other, separated
from one another by an insulating layer. In this case, the electrodes may
be implemented, for example, over a large area or else have a structuring
in, for example, an x/y grid. Also possible in particular in this case is
such an configuration in a grid with many touch sensor elements, with
which it is possible for touching at various locations to be sensed
simultaneously (so-called multi-touch implementation).

[0058] Although an implementation in which the contacting structure is
deposited on the substrate and the at least one electrically conductive,
transparent layer of the touch sensor is partially deposited on the
contacting structure has been described with reference to the
embodiments, also possible, for example, is a converse configuration, in
which the contacting structure is partially deposited on the electrically
conductive, transparent layer. In other words, it is possible when
forming and structuring the layer structure to choose a favorable
sequence, which also takes into consideration in particular the
selectivity in the etching process for the structuring.